The Dairy Jungle

Dairy products take many forms and their origins sometimes appear obscure to us. Raw milk generally comes from cows, but can be obtained from other mammals such as goats, sheep, horses…

The following diagram shows the most common foods derived from milk and how they are created.


CHEESE
Ripening/Renneting
The original goal of cheesemaking was to preserve the nutritional elements of milk (fats and proteins) and remove the fermentable elements (water and sugar) since refrigeration was unavailable in olden times. These elements are separated by two types of milk coagulation:

• Chemical using rennet (renneting)
Rennet is a natural complex of enzymes produced in any mammalian stomach to digest the mother's milk. The active enzyme in rennet called rennin or chymosin coagulates the milk’s proteins, causing it to separate into solids (curds) and liquid (whey). Vegetable rennet can also be made by isolating the coagulating agents of certain plants.

• Biological using bacterial culture (ripening)
The microorganisms most often used are Streptococci and lactobacilli. Cheese cultures are divided into two basic types: mesophilic and thermophilic. These terms describes the temperature the culture thrives at. Mesophilic cultures prefer room temperatures while thermophilic cultures require a higher temperature. The bacteria feed on the lactose of milk and create lactic acid which dissolves calcium. This is why cheeses issued from biological coagulation are poor in calcium and therefore their consistency is rather soft (calcium accelerates moisture loss).

Some cheeses are designed using both bacterial cultures and rennet.

Salting
Salt has a number of roles in cheese besides adding a salty flavor. It preserves cheese from spoiling, draws moisture from the curd, and firms up a cheese’s texture in an interaction with its proteins. Some cheeses are salted from the outside with dry salt or brine washes. Most cheeses have the salt mixed directly into the curds.

MILK
Homogenization & Pasteurization
Milk is often homogenized, a treatment which prevents a cream layer from separating out of the milk. Homogenization confers no health or safety benefits to the milk, only the convenience of not having to shake the bottle before use.
Pasteurization is the partial sterilization of milk at a temperature and for a period of exposure that destroys harmful (and beneficial) organisms as well as enzymes without major chemical alteration of the substance. Pasteurized milk may affect the flavor of cheese.

Separation
The higher butterfat-layer is removed from the top of milk (fat skimming) or separated by centrifugation in commercial settings.

CREAM
Butterfat content determines the classification of a cream. The fat content of light cream is 18 to 30 percent, light whipping cream is 31 to 35 percent, and heavy whipping cream is 36 to 40 percent.
Half-and-half is a milk and cream mixture with 10 to 17 percent fat content.

BUTTER
Aging
Cream is held at low temperatures to crystallize the butterfat globules so the final product has the right consistency.

Churning
Cream is agitated to form butter granules that will increase in size and merge as the process progresses. At the end of churning, there are a semi-solid phase (butter) and a liquid phase (buttermilk).

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